7 Hours - The Magic Number for Sleep

Sleeping < 5 hours a day more than x2 your risk of being diagnosed with angina, coronary heart disease, heart attack or stroke.

How much recovery sleep you need to feel recharged depends on how much sleep you have lost.

In a study, volunteers deprived of 3 hours of sleep a night for 5 nights felt nearly, but not quite, back to normal after 10 hours of sleep.

To help you get the optimal amount of sleep each night, U.S. News & World Report suggests:

"Try removing all electronic media devices - BlackBerry, TV, computer - from your bedroom. These distractions are a prime reason why many of us turn out the lights an hour or two later than we originally intended".